The Bloop...       Last Edit: December 8, 2016
a motorfloater for recreational flying......by Mike Sandlin
 
   
  The Bloop 2 is a simple, slow flying biplane with a small motor.

 


 

                            

 



What is the idea ..?

A motorfloater is an ultralight airplane with a small motor that flies very slow. The pilot sits completely out in the open, flying in a simple and easy way. Flying a motorfloater is a lot like flying a paramotor but with the stability, control, wind tolerance, and crash safety of a light airplane or airchair. Exposed flight is comfortable at low speeds, allows an excellent view, and provides a special kind of flight experience.

The motorfloater differs from other airplanes in having a very light wing loading, allowing slow flight and tight turns.
A motorfloater wing loading is similar to that of a hang glider (less than 2 pounds of gross weight per square foot of wing), and it has a light empty weight  (United States FAR Part 103 compliant, less than 254 lbs.). My idea of a motorfloater differs from paramotors, powered hang gliders, and microtrikes in having a tail (for pitch stability), a fixed rigid wing (again for stability, without fabric canopy issues), and more fixed structure around the pilot (for crash protection). A motorfloater does not try to be everything that heavier airplanes are, it is more of a motor scooter with wings.

Motorfloaters can be made strong  and durable and still stay within the FAR Part 103 weight limits, as long as we are willing to fly without the extraneous weight that comes from doors and windows, big engines and big fuel tanks, heavy tires, brakes and ground steering, electrical systems, extensive instrumentation, and the streamlining associated with high speed flight. All of that heavy stuff is really more of a burden than a benefit if your goal is simply to fly for fun once or twice a week.

I designed and built the Bloops1 through 4, motorfloaters which I have been flying since July, 2011.These have proven to be enjoyable recreational airplanes. The Bloop 3 measured level flight cruise speed is 25 miles per hour, for comfort and casual flying. It is one of the slowest motorized airplanes ever, fulfilling its design goals.

I use simple controls, garage technology construction, and a paramotor engine. The stall and spin characteristics (if any) should be very mild and forgiving, and an unaccelerated stall with moderate weight pilots does not have any abrupt results. At my weight I can fly with the control stick full back and still maneuver, although the nose nods up and down, and the sink rate is high. The emergency parachute is hand deployed, as it might be on a hang glider or a trike, a realistic option when the pilot is out in the open.

The Bloop is built mainly of aluminum tubes bolted together and braced with braided steel cable, covered overall with light but conventional aircraft fabric. This "garage construction" involves using mostly a hand held power drill and a hacksaw. I don't use welding, sheet metal, specially machined parts, jigs, molds, nor any spray rig. The Bloop 4 uses tubes in a length of no more than eight feet, for mail order shipping by the builder.

The Bloop was originially the Pig glider, with an engine added later. (See the Pig Page for details on this airchair glider.)  The Bloop 4 with engine and emergency parachute weighs about 214 pounds. The power package is a
modern paramotor system, a Vittorazi Moster 185 two stroke engine (25 hp.) with a 1.3 meter two bladed propeller. The engine is started by a rope pull (recoil) and uses synthetic oil mixed into the high octane gasoline. In flight I use two instruments: a tachometer (engine crankshaft speed in revolutions per minute) and an exhaust gas temperature gage.

For simplicity,
the Bloop has no ailerons, the plane is controlled by the rudder (or rudders) and elevator only. This is a traditional two axis system (similar to a Weedhopper, Flying Flea, Skypup, early Quicksilver MX, etc.) which requires two axis flying procedures. For example, when you are rolling on the ground in a cross wind, you keep the nose low so the weight is on the wheels, which will keep the wings level. Taking off or landing in a crosswind requires maintaining a crab angle rather than a slip when the wheels are not on the ground. Ordinary flight maneuvers are accomplished with the two axis system in essentially the same way as the three axis system, such that an experienced pilot may soon become indifferent as to which system is in use.
 
I don't taxi much, I walk the plane to and from the runway, which is practical with a well balanced airplane that isn't heavy. A pilot who walks his plane instead of taxing can see better, has better control, will preserve his engine time for flying, and will make less noise and dust around the other airplanes.
In consideration of other air and runway traffic, the Bloop can scoot onto or off the runway with the pilot seated when necessary. Scooting is also good for ground training, allowing a pilot new to the Bloop to learn use of the controls without flying. There is no transition to three axis flight, so ground control is the same as flight control.

 
A motorfloater should be able to roll with the nose low and stop with the nose down, firmly gripping the ground, so it will not be blown away in a strong wind. The wheels of the Bloop are located near the center of balance, so in moderate conditions I can take off and land with the tail down, but if I need a ground brake I can stop with the nose down.

The Bloop is a "put-put" for local flights, just for fun.
This is a non-commercial project, so nothing is for sale, but I encourage commercial production of a motorfloater like this.

All of the materials on my websites are freely available for whatever purposes the user may desire.

Comments After Five Years of Bloop Flying:

Light Wing Loading:
The light wing loading of the Bloops has proven to be a benefit for reasons of easy and comfortable flight. Ordinary winds, especially early or late in the day, have not proven to be restrictively turbulent, or even bothersome.

Part 103 Ultralight: It has been a liberating experience to operate as an ultralight, to build and modify aircraft equipment and procedures without formal oversight. The Bloop 3 has a 74 lb. margin under the Part 103 weight limit (with the 24 lb. parachute allowance), the fuel tank uses only half the 5 gallon allowance, and the airspeed limits are easily met. I would like create a two seat version, even with pilot or usage restrictions, but this is not legal, even as a sport class plane.

Two Axis Control: For simplicity, the Bloop is designed to be controlled by rudder and elevator only, there are no ailerons. Some of the traditionally recognized shortcomings of the rudder/elevator control system have been addressed. The Bloop is designed for a nose down ground roll attitude, which puts the aircraft weight on the widely spaced wheels, keeping the wings level while ground rolling in cross winds. This ability, and the slow airspeeds, have made cross wind conditions a manageable option, as with other kinds of airplanes.  The Bloop has no ailerons but does not lack roll control, it rolls quickly, but the control is indirect rather than direct.

Paramotor Engine: The thrust of the small engine is quite adequate for satisfying flight, and the low rate of fuel consumption is gratifying and makes for a low burden of fuel handling. My birdcage biplane is sometimes spurned as draggy, but who has the most efficient airplane around? The plane with the lowest fuel consumption is the most efficient, and my small engine uses a little over a gallon per hour (a very low rate), so the Bloop is a high efficiency champion!

No Taxi: Lifting the plane by the tail and rolling it like a sailplane, to or from the flight line, instead of taxiing, has been practical and convenient. A true ultralight does not need to be moved with a motor, this often just adds unnecessary weight, complexity, noise, dust, and engine wear.

Hand Deployed Emergency Parachute: My total recovery system is light, easy to inspect, compact and out of the way, as it would be on any paraglider or hang glider. It has not been deployed in flight, but I sometimes pull it out of the bag on the ground as a functional check.

Flight Instruments: Engine temperature and engine speed gages are my only flight instruments, they are needed on the ground for diagnostics but I can't think of any time when they were important in the air. The airspeed reference is nose attitude and wind feel, which is inexact, but being slightly fast or slow is not much of a hazard in the Bloop.

Garage Technology: I use simple parts attached simply, using simple tools. Modificatons, upgrades, repairs and replacements were easy and fast.

Free Standing Center Section: Having a built up center section was a great benefit to Bloop 4 construction, I could attach new parts to it and set everything up without having to assemble the whole airframe in the backyard. It was limited to an eight foot width for possible highway transport, but with the beach wheels it now exceeds that dimension.

Wheels and Skids: Fat BMX bicycle wheels are good for the dirt, easily replaced or repaired locally, and resistant to leaks from thorns when charged with slime. Stiff on landing impact (lacking other elastic suspension), but good enough. The skids are practical but wear out fast on paved runways. Using the nose skid as a ground brake has been simple and adequate. Bloop 3 now uses big, low pressure polyurethane tires, "beach wheels", which are effective for softening landings and rough field rolling. The nose skid is now a 12" bicycle tire, with hard braking always on.
 
Outside Tie Down: The Bloop is tied down in the open all day long. Always being exposed accelerates corrosion, which is not good for the plane in any way, but with the use of cockpit and engine covers, I find it acceptable. With a thorough silvering job the wing fabric can endure the sun exposure. I don't have to maintain a hangar, and can make a quick start.

Open Air Flight: I like this, I feel like I am out there and really flying when I see and feel everything. Low speed flying is comfortable, I often fly in a tee shirt and hiking shorts.

Paramotor Pilot Conversion: I sometimes view the Bloop as a paramotor without canopy issues, perhaps a motorfloater that paramotor pilots can fly with familiarity. The openness, pilot position, engine, two axis control, and slow airspeeds would be familiar, although the greater mass will involve new energy management judgements. Admittedly, the Bloop will have double the wing loading of a paramotor, and thus will have twice the turn radius and will have to fly forty percent faster, but it should still provide an easy flying situation for paramotor pilots compared to the much heavier airplanes. To the paramotor pilot transitioning to a motorfloater I would say, "keep it moving and give it some runway".

Unpaved Runways: Flying off dirt feels soft, stable and more forgiving, compared to pavement.
 
Aircraft Balance:
Bloop 2 had the pilot way forward with 5 degrees of horizontal tail crank holding the tail down, whereas Bloop 3 has the pilot farther back and 3 degrees of tail crank holding the tail down. These setups fly a little differently and each has its advantages.

Aircraft Radio: I use a headset radio because it is required at my airport, but I would need ear protection anyway because of the engine noise. To transmit, I usually throttle back to idle to reduce the engine noise, and even then I don't know if I am being heard. Often I do not clearly hear others. I follow the rules but don't consider my radio to be a substantial contribution to safety unless there is a frequent mix of fast and slow traffic.

Various Airfoils:
I've flown with three different airfoils, they all fly about the same, wing loading seems to be the important factor.

 All versions of the Bloop fly about the same, the differences were introduced for reasons of more practical operation or in favor of minor tradeoffs. The Bloop 2 used a single rudder in the prop wash instead of two side by side rudders, this gave better yaw authority at the very lowest speeds on the ground. The Bloop3 had a free standing center section, allowing the outer wing panels to be removed for transport/storage/maintenance, and the polyhedral angles of the wing panels could be adjusted to varry the yaw/roll coupling.
The landing gear has grown longer, raising the pilot higher in the air, and light balloon tires were tried with good results, except that they needed frequent re-inflation due to thorn punctures. The Bloop 4 uses a simplified nose section (lighter structure and perhaps lighter yaw forces) and high volume bicycle wheels. My current motorfloater is the Bloop 4.

For developments see the Bloop News page. 

  Bloop 4, the latest version of the Bloop, lifts off from an unpaved runway in October, 2016.

 Bloop 4 Technical Drawings (93 drawings + Readme).

These drawing downloads are free and may be used for any purpose.
 
  

    
As bitmaps
,in zip folder download:   Bloop 4 GIF4.zip


      
In a CAD (Computer Assisted Design) format, requiring a CAD program or viewer, 
zip folder download: 

(These DXF drawings are not the best CAD for the Bloop because they were produced from Turbocad TCW, they are buggy, the groupings and layerings are imperfect, the text had to be exloded and looks crude. They are okay for viewing but not the best for rework or modification).


In the native CAD format, highest quality, requiring a Turbocad program,
zip folder download:

   Bloop 4 TCW5.zip

The Bloop 4 Drawings as bitmaps can be viewed online:


Bloop 4 Drawing Online Viewing Page




 Bloop 3 Technical Drawings (93 pages).

These drawing downloads are free and may be used for any purpose.
 
  

  
As bitmaps
,in zip folder download:   Bloop 3 GIF2.zip  

Drawings as bitmaps, viewed online: m-sandlin.info's Gallery 
(The online bitmap drawings will be the first ones updated when changes are made, the online photo captions describe the change, and the date on the drawing will be that of the latest revision. Compare dates of the CAD file drawings to the online versions to see if changes have been made.)

      
In a CAD (Computer Assisted Design) format, requiring a CAD program or viewer, 
zip folder download: 

(These DXF drawings are not the best CAD for the Bloop because they were produced from Turbocad TCW, they are buggy, the groupings and layerings are imperfect, the text had to be exloded and looks crude. They are okay for viewing but not the best for rework or modification).


In the native CAD format, highest quality, requiring a Turbocad program,
zip folder download:



 

 Bloop 2 Technical Drawings (93 pages).

These drawing downloads are free and may be used for any purpose.
 
  

    
As bitmaps
,in zip folder download:    Bloop 2 GIF2.zip

Drawings as bitmaps, viewed online: m-sandlin.info's Gallery 
(The online bitmap drawings will be the first ones updated when changes are made, the online photo captions describe the change, and the date on the drawing will be that of the latest revision. Compare dates of the CAD file drawings to the online versions to see if changes have been made.)

      
In a CAD (Computer Assisted Design) format, requiring a CAD program or viewer, 
zip folder download: 

(These DXF drawings are not the best CAD for the Bloop because they were produced from Turbocad TCW, they are buggy, the groupings and layerings are imperfect, the text had to be exloded and looks crude. They are okay for viewing but not the best for rework or modification).


In the native CAD format, highest quality, requiring a Turbocad program,
zip folder download:







Bloop 1
Technical Drawings (92 pages).
 
These are drawings of the the previous version of the Bloop, the Bloop 1 (twin rudders),
not the the current version, the
Bloop 2 (single rudder). See the Photo Gallery for Bloop 1 photos.
       
As bitmaps
,  zip folder download: Bloop 1 GIF1.zip

Drawings as bitmaps, viewed online: m-sandlin.info's Gallery 
(The online bitmap drawings will be the first ones updated when changes are made, the online photo captions describe the change, and the date on the drawing will be that of the latest revision. Compare dates of the CAD file drawings to the online versions to see if changes have been made.)

In a CAD (Computer Assisted Design) format, requiring a CAD program or viewer, zip folder download:
(These DXF drawings are not the best CAD for the Bloop because they were produced from Turbocad TCW, they are buggy, the groupings and layerings are imperfect, okay for viewing but not the best for rework or modification)

In the native CAD format, requiring a Turbocad program,
zip folder download:

 



Good ventilation and steering with just the rudder pedals!

    
 




[End]